Autonomous driving control device

ABSTRACT

An autonomous driving control device is capable of starting an autonomous driving control without an operation of a driver and reducing a possibility that the driver can not start manual driving. An autonomous driving control is switched to manual driving when a determination section determines that the amount of operation by the driver is equal to or greater than a first threshold, before a predetermined time elapses since the autonomous driving control is automatically started. An autonomous driving control is switched to a manual driving when the determination section determines that the amount of operation by the driver is equal to or greater than a second threshold that is greater than the first threshold, after the predetermined time elapses.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/930,970 filed May 13, 2020 (allowed), which is a continuation of U.S.application Ser. No. 16/018,271 filed Jun. 26, 2018 (now U.S. Pat. No.10,698,405 issued Jun. 30, 2020), which is a continuation of U.S.application Ser. No. 15/413,568, filed Jan. 24, 2017 (now U.S. Pat. No.10,054,942 issued Aug. 21, 2018), which claims priority to JapanesePatent Application No. 2016-044861 filed Mar. 8, 2016. The entiredisclosures of the prior applications are considered part of thedisclosure of the accompanying continuation application, and are herebyincorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an autonomous driving control device.

Background Art

There are known conventional autonomous driving control devices thatperform an autonomous driving control. An example of such autonomousdriving control devices is described in Patent Literature 1, forexample.

According to the autonomous driving control method described in Claim 1of Patent Literature 1, when a control computer determines that avehicle is ready for an autonomous driving control, the control computernotifies a user (driver) that the vehicle is ready. Then, the autonomousdriving control is started when the control computer receives a firstinput indicating that the user (driver) is ready.

Following is a patent literature which the applicant has noticed as arelated art of the present invention.

[Patent Literature 1]: U.S. Pat. No. 8,670,891

Problem to be Solved by Embodiments of the Invention

As described above, in order to start the autonomous driving control,the autonomous driving control device described in Patent Literature 1requires the first input that indicates the user (driver) is ready.Thus, with the autonomous driving control device described in PatentLiterature 1, the user's (driver's) operation for starting theautonomous driving control is complicated.

Besides, if the autonomous driving control is automatically started whenthe driver is wishing to continue performing the manual driving, thedriver wishes to switch from the autonomous driving control to themanual driving. In such a situation, if the switching from theautonomous driving control to the manual driving is difficult, thedriver may be unable to perform the manual driving in spite of thedriver wishing to perform the manual driving.

In view of the problem described above, an object of the embodiment ofthe present invention is to provide an autonomous driving control devicethat can autonomously engage in an autonomous driving control withoutthe need for any operation of a driver to engage the autonomous drivingcontrol and at the same time can reduce the possibility that the driveris unable to perform a manual driving in spite of the driver wishing toperform the manual driving.

SUMMARY

In order to achieve the above described object, the first aspect ofembodiments of the present invention is an autonomous driving controldevice that performs an autonomous driving control of a vehicle. Theautonomous driving control device comprises:

a first determination section that determines whether or not theautonomous driving control can be automatically started;

a second determination section that determines whether or not to switchfrom the autonomous driving control to a manual driving; and

an adjustment section that adjusts a threshold used in the determinationmade by the second determination section,

wherein the autonomous driving control is automatically started when thefirst determination section determines that the autonomous drivingcontrol can be automatically started,

before a predetermined time elapses since the autonomous driving controlis automatically started, the threshold used in the determination madeby the second determination section is adjusted to be a first thresholdby the adjustment section, and switching from the autonomous drivingcontrol to the manual driving is performed when the second determinationsection determines that an amount of operation by a driver is equal toor greater than the first threshold, and

after the predetermined time elapses since the autonomous drivingcontrol is automatically started, the threshold used in thedetermination made by the second determination section is adjusted to bea second threshold which is greater than the first threshold by theadjustment section, and switching from the autonomous driving control tothe manual driving is performed when the second determination sectiondetermines that the amount of operation by the driver is equal to orgreater than the second threshold.

That is, the autonomous driving control device according to the presentinvention can autonomously engage in an autonomous driving control ofthe vehicle. More specifically, the autonomous driving control deviceaccording to the present invention can start the autonomous drivingcontrol without the need for any operation by the driver to start theautonomous driving control.

Therefore, the autonomous driving control device according to thepresent invention can reduce the complexity of the operation by thedriver to start the autonomous driving control and improve the ease ofthe operation to start the autonomous driving control, compared with theautonomous driving control device described in U.S. Pat. No. 8,670,891that requires the first input indicating that the user (driver) is readyin order to engage in the autonomous driving control.

If the autonomous driving control is automatically started when thedriver is wishing to continue performing the manual driving, the driverwishes to switch from the autonomous driving control to the manualdriving. In such a situation, if the switching from the autonomousdriving control to the manual driving is difficult, the driver may beundesirably unable to perform the manual driving in spite of the driverwishing to perform the manual driving.

In view of this, with the autonomous driving control device according tothe present invention, before the predetermined time elapses since theautonomous driving control is automatically started, the autonomousdriving control is switched to the manual driving when the amount ofoperation by the driver becomes equal to or greater than the firstthreshold that is smaller than the second threshold used after thepredetermined time elapses.

That is, with the autonomous driving control device according to thepresent invention, before the predetermined time elapses since theautonomous driving control is automatically started, the driver canswitch from the autonomous driving control to the manual driving with asmaller amount of operation than after the predetermined time elapses.

In other words, with the autonomous driving control device according tothe present invention, the switching from the autonomous driving controlto the manual driving is more easily performed before the predeterminedtime elapses since the autonomous driving control is automaticallystarted than after the predetermined time elapses.

Therefore, with the autonomous driving control device according to thepresent invention, the driver can more readily, or more quickly, startthe manual driving before the predetermined time elapses since theautonomous driving control is automatically started than after thepredetermined time elapses.

As a result, the autonomous driving control device according to thepresent invention can reduce the possibility that the driver is unableto perform the manual driving in spite of the driver wishing to performthe manual driving.

The second aspect of embodiments of the present invention may furthercomprise a notification device that notifies the driver of the automaticstart of the autonomous driving control.

That is, since the autonomous driving control device according to anembodiment of the present invention notifies the driver of the automaticstart of the autonomous driving control, the autonomous driving controldevice can reduce the possibility that the driver fails to be aware thatthe autonomous driving control has been automatically started.

The third aspect of embodiments of the present invention may furthercomprise a notification device that provides the driver a notificationas for the change of the threshold used in the second determinationsection, said change arises due to the adjustment by the adjustmentsection.

That is, with the autonomous driving control device according to anembodiment of the present invention, before the predetermined timeelapses since the autonomous driving control is automatically started,the driver is notified that the threshold used in the determination asfor switching from the autonomous driving control to the manual drivingis smaller than the threshold used after the predetermined time elapses.Therefore, even if the autonomous driving control is automaticallystarted despite the intention of the driver, the autonomous drivingcontrol device according to the embodiment of the present invention canassure the driver that the driver can readily switch from the autonomousdriving control to the manual driving within the predetermined time.

The fourth aspect of embodiments of the present invention furthercomprises a monitor device that monitors a state of the driver, and theadjustment section changes the predetermined time based on the state ofthe driver monitored by the monitor device.

Specifically, with the autonomous driving control device according tothe embodiment of the present invention, the predetermined time in whichswitching from the autonomous driving control to the manual driving ismore easily performed is extended if the monitor device determines thatthe driver has not completed a preparation for engaging the manualdriving, for example. On the other hand, the predetermined time in whichswitching from the autonomous driving control to the manual driving ismore easily performed is shortened if the monitor device determines thatthe driver has no intention to perform the manual driving, for example.

Thus, compared with the case where the length of the predetermined timeis not changed, the autonomous driving control device according to theembodiment of the present invention can reduce the possibility thatswitching from the autonomous driving control to the manual drivingoccurs despite the intention of the driver.

Advantages of Embodiments of the Present Invention

According to the present invention, the autonomous driving control canbe started without the need for any operation by the driver to start theautonomous driving control, and the possibility that the driver isunable to perform the manual driving in spite of the driver wishing toperform the manual driving can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram for explaining the configuration of anautonomous driving control device according to a first embodiment of thepresent invention;

FIG. 2 is a diagram for explaining characteristic parts of theautonomous driving control device according to the first embodiment ofthe present invention; and

FIG. 3 is a flowchart for explaining procedures such as a judgmentconducted by a judgement portion 16 b of the autonomous driving controlunit according to the first embodiment of the present invention.

DETAILED DESCRIPTION

In the following, an autonomous driving control device according to afirst embodiment of the present invention will be described. FIG. 1 is aschematic diagram showing a configuration of the autonomous drivingcontrol device according to the first embodiment.

In the example shown in FIG. 1, an autonomous driving control device 100is mounted on a vehicle (not shown), such as an automobile. Theautonomous driving control device 100 performs an autonomous drivingcontrol for the vehicle. The term “autonomous driving control” means acontrol that does not require the driver of the vehicle to perform anydriving operation, such as acceleration, deceleration and steering ofthe vehicle.

The autonomous driving control includes a lane keeping assist control,for example. According to the lane keeping assist control, steeringwheels (not shown) are autonomously steered (that is, without the needfor the driver to perform a steering operation) so that the vehicle isprevented from going out from its traffic. That is, with the lanekeeping assist control, the steering wheel is autonomously operated tokeep the vehicle traveling within a traffic lane, even if the driverdoes not perform any steering operation.

The autonomous driving control includes a navigation control, forexample. In the navigation control, if there is no other vehicle aheadof the vehicle, a constant speed control to keep the vehicle travelingat a preset constant speed occurs, and if there is another vehicle aheadof the vehicle, a follow-after control to adjust the speed of thevehicle in accordance with the distance from the other vehicle ahead ofthe vehicle.

In the example shown in FIG. 1, a comparison object is used. Thecomparison object is converted into a numerical value for comparisonwith a threshold. The threshold is used for determining whether theautonomous driving control should be switched to a manual driving. Thatis, the autonomous driving control device 100 switches from theautonomous driving control to the manual driving when the comparisonobject is equal to or greater than the threshold.

For example, the amount of steering, the amount of acceleration or theamount of braking operated by the driver during the autonomous drivingcontrol is used as the comparison object. The autonomous driving controldevice 100 switches from the autonomous driving control to the manualdriving if any of the amounts of steering, acceleration and braking isequal to or greater than a threshold. It should be noted that the amountof steering includes a steering workload. The steering workload isdescribed in detail in JP 2015-063244A.

The manual driving is a driving mode in which the vehicle travels basedprimarily on the driving operation by the driver, for example. Themanual driving includes a driving mode in which the vehicle travelsbased only on the driving operation by the driver, for example. Themanual driving also includes a driving mode in which the vehicle travelsbased primarily on the driving operation by the driver and secondarilyon a driving operation assist control that assists the driving operationby the driver.

For example, the case in which the driving operation assist control isexecuted during the manual driving occurs when any of the steeringoperation, the accelerator operation and the brake operation are mainlydone by the driver, and the autonomous driving control device 100performs any of the steering operation, the accelerator operation andthe brake operation which are not primarily done by the driver.Alternatively, the amount of manual operation by the driver, such assteering, accelerator or brake operation, may be adjusted by addition orsubtraction of the amount of operation computed by the driving operationassist control.

In the example shown in FIG. 1, the autonomous driving control device100 includes an external sensor unit 1, a global positioning system(GPS) receiver unit 2, an internal sensor unit 3, a map database 4, anavigation system 5, an actuator unit 6, a human machine interface (HMI)7, a monitor device 8, a shift lever 9, an auxiliary unit U, and anelectronic control unit (ECU) 10.

In the example shown in FIG. 1, the external sensor unit 1 serves as adetector that detects an external condition and provides peripheralinformation about the vehicle. The external sensor unit 1 includes atleast one of a camera, a radar, and a LIDAR (Laser Imaging Detection AndRanging sensor).

The camera is an imaging device that images the external condition ofthe vehicle. The camera is mounted on the back side of a windshield ofthe vehicle, for example. The camera may be a monocular camera or astereoscopic camera. The stereoscopic camera has two imaging partsdisposed to reproduce a binocular parallax, for example. The imaginginformation obtained with the stereoscopic camera includes depthinformation. The camera outputs imaging information on the externalcondition of the vehicle to the ECU 10. The camera may be a visiblelight camera or an infrared camera.

The radar detects obstacles outside the vehicle using a radio wave. Theradio wave is of a millimeter wave, for example. The radar transmits aradio wave around the vehicle and detects an obstacle by receiving theradio wave reflected from the obstacle. The radar can output thedistance to the obstacle, the direction of the obstacle or the likes asobstacle information. The radar provides the information about thedetected obstacle to the ECU 10. When a sensor fusion should beexecuted, the information about the received reflected radio wave may beprovided to the ECU 10.

The LIDAR sensor detects an obstacle outside the vehicle while utilizinglight. The LIDAR sensor emits light around the vehicle, then measuringthe distance to the point of reflection and detecting an obstacle byreceiving the light reflected from the obstacle. The LIDAR sensor canprovide obstacle information, such as the distance to the obstacle orthe direction of the obstacle. The LIDAR sensor outputs the informationabout the detected obstacle to the ECU 10. When sensor fusion should beexecuted, the information about the received reflected light may beprovided to the ECU 10. The camera, the LIDAR sensor and the radar donot always have to be provided in combination.

In the example shown in FIG. 1, the GPS receiver unit 2 receives signalsfrom three or more GPS satellites to provide positional informationabout the position of the vehicle. The positional information includesthe latitude and longitude, for example. The GPS receiver unit 2 outputsthe positional information about the measured position of the vehicle tothe ECU 10.

In other examples, the GPS receiver unit 2 may be replaced with othermeans capable of determining the latitude and longitude of the vehicle.

In the example shown in FIG. 1, the internal sensor unit 3 serves as adetector that provides information about the traveling condition of thevehicle and about the amount of any of the steering operation, theaccelerator operation and the brake operation by the driver of thevehicle (the amounts of operation include the steering workloaddescribed above). In order to obtain the information about the travelingcondition of the vehicle, the internal sensor unit 3 includes at leastone of a speed sensor, an acceleration sensor unit and a yaw ratesensor. Further, in order to detect the amount of the operation, theinternal sensor unit 3 includes at least one of a steering sensor, anaccelerator pedal sensor and a brake pedal sensor.

The speed sensor is a detector that detects the speed of the vehicle.For example, the speed sensor is a wheel speed sensor that is mounted ona wheel of the vehicle or a drive shaft that rotates integrally with thewheel and detects the rotational speed of the wheel. The speed sensoroutputs speed information (wheel speed information) including the speedof the vehicle to the ECU 10.

The acceleration sensor unit serves a detector that detects theacceleration of the vehicle. The acceleration sensor unit includes alongitudinal acceleration sensor that detects the acceleration of thevehicle in the longitudinal direction and a lateral acceleration sensorthat detects the acceleration of the vehicle in the lateral direction,for example. The acceleration sensor unit outputs accelerationinformation including the acceleration of the vehicle to the ECU 10.

The yaw rate sensor is a detector that detects the yaw rate (rotationalangular velocity) of the center of gravity of the vehicle around thevertical axis. For example, a gyro sensor is used as the yaw ratesensor. The yaw rate sensor outputs yaw rate information including theyaw rate of the vehicle to the ECU 10.

The steering sensor is a detector that detects the amount of operationof the steering wheel (the amount of steering operation) by the driverof the vehicle, for example. The amount of steering operation detectedby the steering sensor is a steering angle of the steering wheel or asteering torque on the steering wheel, for example. The steering sensoris mounted on a steering shaft of the vehicle, for example. The steeringsensor outputs information including the steering angle of the steeringwheel or the steering torque on the steering wheel to the ECU 10.

The accelerator pedal sensor is a detector that detects the amount ofdepression of the accelerator pedal, for example. The amount ofdepression of the accelerator pedal is indicated by the positon of theaccelerator pedal (pedal position) with respect to a predeterminedposition, for example. The predetermined position may be a fixedposition or a position that varies with a predetermined parameter. Theaccelerator pedal sensor is mounted on a shaft part of the acceleratorpedal of the vehicle, for example. The accelerator pedal sensor outputsoperation information which accords with the amount of depression of theaccelerator pedal to the ECU 10.

The brake pedal sensor is a detector that detects the amount ofdepression of the brake pedal, for example. The amount of depression ofthe brake pedal is indicated by the positon of the brake pedal (pedalposition) with respect to a predetermined position, for example. Thepredetermined position may be a fixed position or a position that varieswith a predetermined parameter. The brake pedal sensor is mounted on apart of the brake pedal, for example. The brake pedal sensor may detectthe operating force on the brake pedal (such as the force to depress thebrake pedal or the pressure of the master cylinder). The brake pedalsensor outputs operation information which accords with the amount ofdepression of or the operating force on the brake pedal to the ECU 10.

In the example shown in FIG. 1, the map database 4 is a database thatstores map information. The map database 4 is implemented in a hard diskdrive (HDD) mounted on the vehicle, for example. The map informationincludes road location information, road shape information andpositional information about intersections and branches, for example.The road shape information includes road types, such as curves orstraight roads, or the curvature of curves, for example. The mapinformation may further include an output signal of the external sensorunit 1, when the autonomous driving control device 100 uses positionalinformation about obstructions, such as buildings and walls, or thesimultaneous localization and mapping (SLAM) technology.

In other examples, the map database 4 may be stored in a computer at aninfrastructure, such as an information processing center, that cancommunicate with the vehicle.

In the example shown in FIG. 1, the navigation system 5 is a device thatguides the driver of the vehicle to a destination set on the map by thedriver of the vehicle.

The navigation system 5 calculates a route along which the vehicle is totravel, based on the positional information about the vehicle obtainedby the GPS receiver unit 2 and the map information in the map database4. In the route, a lane within which the vehicle is to travel in amultilane section may be specified, for example. The navigation system 5calculates a desired route from the current position of the vehicle to adestination, and notifies the driver of the desired route through anindication on a display or an audio output of a speaker, for example.The navigation system 5 outputs information about the desired route forthe vehicle to the ECU 10, for example.

In the example shown in FIG. 1, the navigation system 5 uses thepositional information about the vehicle obtained by the GPS receiverunit 2 and the map information in the map database 4. In other example,alternatively, the navigation system 5 may use information stored in acomputer at an infrastructure, such as an information processing center,that can communicate with the vehicle. Alternatively, part of theprocessing performed by the navigation system 5 may be performed by thecomputer at the infrastructure.

In the example shown in FIG. 1, the actuator unit 6 is a device thatcontrols a travelling of the vehicle. The actuator unit 6 includes atleast a throttle actuator, a brake actuator and a steering actuator.

In the example shown in FIG. 1, the throttle actuator controls theamount of air supply to the engine (throttle opening) in response to acontrol signal from the ECU 10, thereby controlling the driving force ofthe vehicle.

In other examples where the vehicle is an electric vehicle, the actuatorunit 6 does not include the throttle actuator but has a motor serving asa motive power source and receives a control signal for the motor fromthe ECU 10 to control the driving force of the vehicle.

The brake actuator controls a brake system in response to the controlsignal from the ECU 10, thereby controlling the braking force to beapplied to the wheels of the vehicle. The brake system may be ahydraulic brake system, for example.

The steering actuator controls driving of an assistant motor, whichcontrols the steering torque, of an electric power steering system inresponse to the control signal from the ECU 10. In this way, thesteering actuator controls the steering torque of the vehicle.

In the example shown in FIG. 1, the HMI 7 is an interface for output andinput of information between an occupant (including the driver) of thevehicle and the autonomous driving control device 100. The HMI 7includes a display panel on which image information is shown to theoccupant, a speaker for audio output, and a manipulation button or atouch panel with which the occupant can perform an input operation, forexample. The HMI 7 may output information to the occupant through apersonal digital assistant connected thereto by radio or receive aninput operation by the occupant through the personal digital assistant.

In the example shown in FIG. 1, the monitor device 8 monitors the stateof the driver. The monitor device 8 can check a manual drivingpreparation state of the driver. More specifically, the monitor device 8can check whether or not the driver has completed a preparation to startthe manual driving, for example. Alternatively, the monitor device 8 canalso check whether or not the driver has an intention to perform themanual driving, for example.

The monitor device 8 may be a camera capable of imaging the driver, forexample, which is used in estimation of the degree of eye opening or thedirection of the line of sight of the driver, for example.Alternatively, the monitor device 8 may be a camera that images thehands of the driver, for example, which is used to determine by imageanalysis whether or not the driver is holding the steering wheel, forexample. Alternatively, the monitor device 8 may be a touch sensor(distortion sensor) that detects the strength of the grip on thesteering wheel, such as the touch sensor described in JP11-091397A, forexample.

In the example shown in FIG. 1, the shift lever 9 is provided. As forthe shift lever 9, there is provided a shift position for a mode inwhich the autonomous driving control can be automatically started.

In the example shown in FIG. 1, the auxiliary unit U is typically adevice that can be operated by the driver of the vehicle. The auxiliaryunit U is a generic term of devices that are not included in theactuator unit 6.

In the example shown in FIG. 1, the auxiliary unit U includes turnsignals, headlamps, or wipers, for example.

In the example shown in FIG. 1, the ECU 10 performs the autonomousdriving control of the vehicle. The ECU 10 has a central processing unit(CPU), a read only memory (ROM), and a random access memory (RAM), forexample.

In the example shown in FIG. 1, the ECU 10 has an input part 11, arecognition part 12, a travel plan generation part 13, a calculationpart 14, an output part 15, and a control part 16. The ECU 10 performsthe controls of the above parts by executing a program loaded from theROM into the RAM at the CPU. The ECU 10 may be composed of a pluralityof electronic control units.

In the example shown in FIG. 1, the input part 11 acquires the amountsof steering operation, accelerator operation and brake operation by thedriver of the vehicle during the autonomous driving control (the amountsof operation also include the steering workload described above) as wellas the amounts of steering operation, accelerator operation and brakeoperation by the driver of the vehicle during the manual driving (theamounts of operation also include the steering workload describedabove), based on the information obtained by the internal sensor unit 3.The amounts of operation include the steering angle of the steeringwheel, the steering torque on the steering wheel, the steering workload,the amount of depression of the accelerator pedal, the amount ofdepression of the brake pedal, and the operating force on the brakepedal, for example. Alternatively, the amounts of operation may includea duration of a state where the steering angle of the steering wheel,the steering torque on the steering wheel, the steering workload, theamount of depression of the accelerator pedal, the amount of depressionof the brake pedal, the operating force on the brake pedal or the likeis equal to or greater than a preset threshold.

In the example shown in FIG. 1, the recognition part 12 recognizes theenvironment surrounding the vehicle based on the information obtained bythe external sensor unit 1 or the GPS receiver unit 2 or the informationin the map database 4. The recognition part 12 has an obstaclerecognition part (not shown), a road width recognition part (not shown),and an infrastructure recognition part (not shown), for example.

The obstacle recognition part recognizes obstacles around the vehicle asthe environment surrounding the vehicle based on the informationobtained by the external sensor unit 1. Obstacles recognized by theobstacle recognition part include a pedestrian, another vehicle, amoving object such as a motorcycle and a bicycle, a lane line (a whiteline or a yellow line), a curb, a guard rail, a pole and a median stripon a road, and a static object such as a building and a tree. Theobstacle recognition part acquires information about the distancebetween the obstacle and the vehicle, the location of the obstacle, thedirection, the relative speed and the relative acceleration of theobstacle with respect to the vehicle, and the type and the attribute ofthe obstacle. The types of the obstacle include a pedestrian, anothervehicle, a moving object, a static object, and the like. The attributeof the object is a property of the obstacle, such as the hardness andthe shape of the obstacle.

The road width recognition part recognizes the width of the road onwhich the vehicle is traveling as the environment surrounding thevehicle based on the information obtained by the external sensor unit 1and the GPS receiver unit 2 as well as the information in the mapdatabase 4.

The infrastructure recognition part recognizes, as the environmentsurrounding the vehicle, whether or not the vehicle is traveling acrossan intersection or in a parking area based on the map information in themap database 4 and the positional information about the vehicle obtainedby the GPS receiver unit 2. The infrastructure recognition part mayrecognize, as the environment surrounding the vehicle, whether or notthe vehicle is traveling in a school zone, the vicinity of a childcarefacility, the vicinity of a school, the vicinity of a park or the likebased on the map information and the positional information about thevehicle.

In the example shown in FIG. 1, the travel plan generation part 13generates a travel plan for the vehicle based on the desired routecalculated by the navigation system 5, the information about an obstaclearound the vehicle recognized by the recognition part 12, and the mapinformation in the map database 4.

The travel plan is a trajectory along which the vehicle is to move onthe desired route. The travel plane includes the speed, theacceleration, the deceleration, the direction, the steering or the likeof the vehicle at different points in time, for example.

The travel plan generation part 13 generates a travel plan that allowsthe vehicle to travel on the desired route by meeting safety, statutoryand efficiency requirements. Furthermore, the travel plan generationpart 13 generates the travel plan for the vehicle so as to avoidcollision with an obstacle, based on the situation of obstacles aroundthe vehicle.

In the example shown in FIG. 1, the calculation part 14 calculates athreshold used in the determination of whether or not to switch from theautonomous driving control to the manual driving, based on the amountsof operation (the amounts of operation may include the steering workloaddescribed above) by the driver of the vehicle during the autonomousdriving control obtained by the input part 11.

For example, the ECU 10 stores a function of a threshold and the amountsof operation by the driver of the vehicle (the amount of operation mayinclude the steering workload described above). The function is used tocalculate the threshold used in the determination of whether or not toswitch from the autonomous driving control to the manual driving by thecalculation part 14.

In the example shown in FIG. 1, for example, the output part 15 displaysthe threshold used in the determination of whether or not to switch fromthe autonomous driving control to the manual driving calculated by thecalculation part 14 on a display of the HMI 7.

Specifically, for example, the output part 15 displays the thresholdused in the determination of whether or not to switch from theautonomous driving control to the manual driving during the autonomousdriving control.

In the example shown in FIG. 1, the control part 16 automaticallycontrols traveling of the vehicle based on the travel plan generated bythe travel plan generation part 13. The control part 16 outputs acontrol signal based on the travel plan to the actuator unit 6. That is,the autonomous driving control of the vehicle is achieved by the controlpart 16 controlling the actuator unit 6 based on the travel plan.

During the autonomous driving control of the vehicle, the control part16 switches from the autonomous driving control to the manual driving ifan amount of operation by the driver obtained by the input part 11 (theamount of operation may include the steering workload described above)becomes equal to or greater than the threshold calculated by thecalculation part 14.

FIG. 2 is a diagram for illustrating characteristic parts of theautonomous driving control device according to the first embodiment.

In the example shown in FIG. 2, the control part 16 (see FIGS. 1 and 2)has a determination section 16 a that determines whether or not theautonomous driving control by the autonomous driving control device 100can be automatically started. The determination section 16 a is composedof N of determination sub-sections 16 a 1, 16 a 2, - - - and 16 aN, forexample. The determination section 16 a makes the determinationdescribed below with regard to information other than the intention ofthe driver.

For example, the determination sub-section 16 a 1 determines whether ornot the autonomous driving control can be automatically started, basedon the difference between the position of the vehicle calculated basedon the signal received by the GPS receiver unit 2 (see FIG. 1) and theactual position of the vehicle calculated based on the output signalfrom the external sensor unit 1 (see FIG. 1) and the map information inthe map database 4 (see FIG. 1), for example.

For example, the determination sub-section 16 a 2 determines whether ornot the autonomous driving control can be automatically started, basedon the curvature of the road on which the vehicle is traveling.

The determination section 16 a determines that the autonomous drivingcontrol can be automatically started, if all of the N of determinationsub-sections 16 a 1, 16 a 2, - - - and 16 aN determine that theautonomous driving control can be automatically started.

In the example shown in FIG. 2, the determination section 16 a functionsas a first determination section that determines whether or not theautonomous driving control can be automatically started.

In the example shown in FIG. 2, the control part 16 (see FIGS. 1 and 2)has a determination section 16 b that determines whether or not there isa trigger for terminating the autonomous driving control. Thedetermination section 16 b is composed of M of determinationsub-sections 16 b 1, 16 b 2, . . . and 16 bM, for example. Thedetermination section 16 b makes the determination described below whena certain operation is intentionally performed by the driver.

For example, the determination sub-section 16 b 1 determines whether ornot switching from the autonomous driving control to the manual drivingshould be performed, based on the amount of steering operation (theamount of operation may include the steering workload described above)by the driver of the vehicle during the autonomous driving controlobtained by the input part 11 (see FIG. 1).

For example, the determination sub-section 16 b 2 determines whether ornot switching from the autonomous driving control to the manual drivingshould be performed, based on the amount of accelerator or brakeoperation by the driver of the vehicle during the autonomous drivingcontrol obtained by the input part 11.

The determination section 16 b determines that switching from theautonomous driving control to the manual driving should be performed, ifat least any one of the M of determination sub-sections 16 b 1, 16 b 2 .. . and 16 bM determines that switching from the autonomous drivingcontrol to the manual driving should be performed.

In the example shown in FIG. 2, the determination section 16 b functionsas a second determination section that determines whether or not toswitch from the autonomous driving control to the manual driving.

As described above, the determination sub-sections 16 a 1, 16 a 2, . . .16 aN and the determination sub-sections 16 b 1, 16 b 2, . . . 16 bMhave essentially different determination criteria.

In the example shown in FIG. 2, the control part 16 (see FIGS. 1 and 2)has a determination section 16 c that makes a final determination ofwhether or not the autonomous driving control can be performed, and anautonomous driving control section 16 d that performs the autonomousdriving control.

The determination section 16 c determines that the autonomous drivingcontrol can be automatically started, if all of the N of determinationsub-sections 16 a 1, 16 a 2, . . . 16 aN determine that the autonomousdriving control can be automatically started.

If the determination section 16 c determines that the autonomous drivingcontrol can be automatically started, the autonomous driving controlsection 16 d autonomously engaged in the autonomous driving control.

On the other hand, if at least any one of the M of determinationsub-sections 16 b 1, 16 b 2, . . . 16 bM determines that switching fromthe autonomous driving control to the manual driving should beperformed, the determination section 16 c determines that switching fromthe autonomous driving control to the manual driving should beperformed. Then, the autonomous driving control by the autonomousdriving control section 16 d is stopped, and the manual driving by thedriver occurs. That is, a determination that switching from theautonomous driving control to the manual driving should be performedmade by any of the M of determination sub-sections 16 b 1, 16 b 2, . . .16 bM serves as a trigger for terminating the autonomous drivingcontrol.

In the example shown in FIG. 2, the output part 15 (see FIGS. 1 and 2)has a control state notification section 15 a that notifies the driverthat the autonomous driving control is being performed, for example.

When the autonomous driving control is automatically started, thecontrol state notification section 15 a provides an indication that theautonomous driving control is being performed on the display of the HMI7, for example.

When switching from the autonomous driving control to the manual drivingis performed, the control state notification section 15 a provides anindication that the autonomous driving control is not being performed(in other words, the manual driving is being performed) on the displayof the HMI 7, for example.

In the example shown in FIG. 2, after the autonomous driving control isstarted, the determination section 16 b determines whether or notswitching from the autonomous driving control to the manual drivingshould be performed.

For example, the determination sub-section 16 b 1 determines whether ornot switching from the autonomous driving control to the manual drivingshould be performed, based on the amount of steering operation (theamount of operation may include the steering workload described above)by the driver of the vehicle during the autonomous driving controlobtained by the input part 11 (see FIG. 1).

For example, the determination sub-section 16 b 2 determines whether ornot switching from the autonomous driving control to the manual drivingshould be performed, based on the amount of accelerator or brakeoperation by the driver of the vehicle during the autonomous drivingcontrol obtained by the input part 11.

That is, the determination section 16 b determines whether or notswitching from the autonomous driving control to the manual drivingshould be performed, based on the amount of operation (the amount ofoperation may include the steering workload described above) by thedriver of the vehicle during the autonomous driving control obtained bythe input part 11.

In the example shown in FIG. 2, the calculation part 14 (see FIGS. 1 and2) has an adjustment section 14 a that adjusts a threshold used in thedetermination section 16 b for determining whether or not to switch fromthe autonomous driving control to the manual driving.

Specifically, the adjustment section 14 a adjusts the threshold used inthe determination section 16 b for the above determination so thatswitching from the autonomous driving control to the manual driving ismore easily performed before a predetermined time elapses since theautonomous driving control is automatically started than after thepredetermined time elapses.

More specifically, the threshold used in the determination section 16 bfor the above determination is adjusted to be a first threshold by theadjustment section 14 a before the predetermined time elapses since theautonomous driving control is automatically started. After thepredetermined time elapses, the threshold used in the determinationsection 16 b for the above determination is adjusted to be a secondthreshold greater than the first threshold by the adjustment section 14a.

The second threshold may be set as a fixed value in advance.Alternatively, the second threshold may not be set as a fixed vale butbe set by a function of a state of a vehicle such as the speed of thevehicle, or a state of a driver such as the awareness of the driver.Alternatively, the second threshold may be set as a fixed value inadvance and then be varied according to the state of the vehicle such asthe speed of the vehicle, or the state of the driver such as theawareness of the driver. Specifically, the second threshold is used fordetermining whether or not there is an override. The second threshold isat least a value that is determined independently of the timing when theautonomous driving control is started or disstarted.

The second threshold is set so that there is an instant when the amountof operation (the amount of operation may include the steering workloaddescribed above) by the driver exceeds the second threshold while themanual driving by the driver is being performed.

The determination of whether to stop the autonomous driving control canbe made not only based on the comparison between the amount of operationand the threshold such as the example described above but also based onwhether a specific operation is done by the driver or not. For example,the determination can be made based on whether a turn signal operationis done or not.

In embodiments of the present invention, after the predetermined timeelapses since the autonomous driving control is started, thedetermination section 16 b does not determine that switching from theautonomous driving control to the manual driving even if the driverperforms a turn signal operation. However, before the predetermined timeelapses, the determination section 16 b determines that switching fromthe autonomous driving control to the manual driving should be performedwhen the driver performs a turn signal operation. That is, inembodiments of the present invention, switching from the autonomousdriving control to the manual driving is more easily performed beforethe predetermined time elapses.

FIG. 3 is a flowchart for illustrating processings including thedetermination made by the determination section 16 b or the likes of theautonomous driving control device according to the first embodiment.

Once the routine shown in FIG. 3 is started, first, in Step S100, thedetermination sections 16 a and 16 c (see FIG. 2) determine whether ornot the autonomous driving control can be automatically started. If theresult of the determination is affirmative, the routine proceeds to StepS101. If the result of the determination is negative, the routine ends.

In Step S101, the autonomous driving control section 16 d (see FIG. 2)automatically starts the autonomous driving control without the need forany operation by the driver.

In Step S102, the ECU 10 (see FIG. 1) then determines whether or notthere is an operation by the driver (more specifically, an operation bythe driver that interferes with the autonomous driving control), basedon the amount of operation by the driver (the amount of operation mayinclude the steering workload described above) detected by the internalsensor unit 3 (see FIG. 1), for example. If the result of thedetermination is affirmative, the routine proceeds to Step S103. If theresult of the determination is negative, the routine proceeds to StepS107.

In Step S103, for example, the ECU 10 determines whether or not apredetermined time has elapsed since the autonomous driving control isautomatically started. If the result of the determination isaffirmative, the routine proceeds to Step S104. If the result of thedetermination is negative, the routine proceeds to Step S105.

In Step S104, the determination section 16 b (see FIG. 2) determineswhether or not the amount of operation (the amount of operation mayinclude the steering workload described above) is equal to or greaterthan the first threshold. If the result of the determination isaffirmative, it is determined that the driver wishes to switch from theautonomous driving control to the manual driving, and the routineproceeds to Step S106. On the other hand, if the result of thedetermination is negative, it is determined that the driver wishes tokeep the autonomous driving control, and the routine proceeds to StepS107.

In Step S105, the determination section 16 b (see FIG. 2) determineswhether or not the amount of operation (the amount of operation mayinclude the steering workload described above) is equal to or greaterthan the second threshold. If the result of the determination isaffirmative, it is determined that the driver wishes to switch from theautonomous driving control to the manual driving, and the routineproceeds to Step S106. On the other hand, if the result of thedetermination is negative, it is determined that the driver wishes tokeep the autonomous driving control, and the routine proceeds to StepS107.

Specifically, in the example shown in FIG. 3, the first threshold inStep S104 is set at a smaller value than the second threshold in StepS105.

That is, in the example shown in FIG. 3, the adjustment section 14 a(see FIG. 2) adjusts the thresholds used in the determination made bythe determination section 16 b (see FIG. 2) so that switching from theautonomous driving control to the manual driving is more easilyperformed (in other words, the result of the determination in Step S104is more likely to be affirmative) before the predetermined time elapsessince the autonomous driving control is automatically started than afterthe predetermined time elapses.

In the example shown in FIG. 3, the predetermined time is set to be 2seconds, for example, and the first threshold is set to be one third ofthe second threshold, for example.

In Step S106, the autonomous driving control is terminated, andswitching from the autonomous driving control to the manual driving isperformed.

In Step S107, the autonomous driving control by the autonomous drivingcontrol section 16 d (see FIG. 2) is maintained.

In an application of the autonomous driving control device according tothe first embodiment, the autonomous driving control can beautomatically started by the autonomous driving control section 16 d(see FIG. 2) without the need for any operation by the driver. Inaddition, the autonomous driving control can also be started by anoperation by the driver.

Specifically, for example, the ignition of the vehicle is first switchedon, and the control part 16 then determines whether or not theautonomous driving control can be started, based on the environmentsurrounding the vehicle recognized by the external sensor unit 1 and therecognition part 12 of the ECU 10. If the autonomous driving control canbe started, the control part 16 notifies the driver through the HMI 7that the autonomous driving control can be started. When the driver thenperforms a predetermined input operation, the autonomous driving controldevice 100 starts the autonomous driving control.

In another application of the autonomous driving control deviceaccording to the first embodiment, the autonomous driving control device100 may be configured so that the autonomous driving control cannot bestarted by any operation by the driver.

In the example shown in FIG. 3, the first threshold is fixed at aconstant value until the predetermined time elapses since the autonomousdriving control is automatically started. In another example,alternatively, the first threshold may be set to be a third of thesecond threshold, for example, at the point in time when the autonomousdriving control is automatically started, and may be then graduallychanged to be equal to the second threshold when the predetermined timeelapses since the autonomous driving control is automatically started.

In other words, with the autonomous driving control device according tothe first embodiment, the autonomous driving control of the vehicle canbe automatically started by the autonomous driving control section 16 d(see FIG. 2). That is, the autonomous driving control device accordingto the first embodiment can start the autonomous driving control withoutthe need for any operation by the driver to start the autonomous drivingcontrol.

Therefore, compared with the case where an input that indicates that thedriver is ready is required to start the autonomous driving control, theautonomous driving control device according to the first embodiment canreduce the complexity of the driver's operation to start the autonomousdriving control and improve the ease of the operation to engage theautonomous driving control.

On the other hand, if the autonomous driving control is automaticallystarted in spite of the driver wishing to perform the manual driving,the driver wishes to switch from the autonomous driving control to themanual driving. In such a situation, if the switching from theautonomous driving control to the manual driving is difficult toperform, the driver may be undesirably unable to perform the manualdriving in spite of the driver wishing to perform the manual driving.

In view of this, with the autonomous driving control device according tothe first embodiment, before the predetermined time elapses since theautonomous driving control is automatically started, switching from theautonomous driving control to the manual driving is performed in StepS106 (see FIG. 3) if it is determined in Step S104 (see FIG. 3) that theamount of operation (the amount of operation may include the steeringworkload described above) is equal to or greater than the firstthreshold which is smaller than the second threshold used after thepredetermined time elapses.

That is, with the autonomous driving control device according to thefirst embodiment, the driver can switch from the autonomous drivingcontrol to the manual driving by a smaller amount of operation (theamount of operation may be the steering workload described above) beforethe predetermined time elapses since the autonomous driving control isautomatically started than after the predetermined time elapses.

In other words, with the autonomous driving control device according tothe first embodiment, switching from the autonomous driving control tothe manual driving is more easily performed before the predeterminedtime elapses since the autonomous driving control is automaticallystarted than after the predetermined time elapses.

Therefore, with the autonomous driving control device according to thefirst embodiment, the driver can more readily, or more quickly, engagein the manual driving before the predetermined time elapses since theautonomous driving control is automatically started than after thepredetermined time elapses.

As a result, the autonomous driving control device according to thefirst embodiment can reduce the possibility that the driver is unable toperform the manual driving in spite of the driver wishing to perform themanual driving.

Furthermore, the autonomous driving control device according to thefirst embodiment includes the control state notification section 15 a(see FIG. 2) that functions as a notification device that notifies thedriver of the automatic start of the autonomous driving control.Therefore, the autonomous driving control device according to the firstembodiment can reduce the possibility that the driver fails to be awarethat the autonomous driving control has been automatically started.

It should be noted that the control state notification section 15 a canbe omitted in a second embodiment of the present invention.

In the first embodiment described above, the control state notificationsection 15 a also serves as a notification device that notifies thedriver that the thresholds used in the determinations in Steps S104 andS105 (see FIG. 3) made by the determination section 16 b (see FIG. 2)are adjusted by the adjustment section 14 a (see FIG. 2) so that theyare different between before and after the predetermined time elapses.

That is, the autonomous driving control device according to the firstembodiment notifies the driver, before the predetermined time elapsessince the autonomous driving control is automatically started, that thethreshold used in the determination of whether or not to switch from theautonomous driving control to the manual driving is smaller than thethreshold used after the predetermined time elapses. Therefore, even ifthe autonomous driving control is automatically started despite theintention of the driver, the autonomous driving control device accordingto the first embodiment can assure the driver that the driver canreadily switch from the autonomous driving control to the manual drivingwithin the predetermined time.

Means for notifying that the threshold used before the predeterminedtime elapses and the threshold used after the predetermined time elapsesare different may be a sound, an image indication, or a vibration of thesteering wheel, for example.

In a third embodiment of the present invention, the control statenotification section 15 a that served as the above describednotification device that notifies the driver of the variation of thethresholds can be omitted.

With the autonomous driving control device according to the firstembodiment, the monitor device 8 (see FIG. 1) monitors the state of thedriver. In accordance with the state of the driver monitored by themonitor device 8, the length of the predetermined time in Step S103 inFIG. 3 is changed by the adjustment section 14 a (see FIG. 2).

More specifically, with the autonomous driving control device accordingto the first embodiment, the length of the predetermined time in whichsmaller threshold is used is increased if the monitor device 8determines that the driver has not completed a preparation to engage inthe manual driving, for example. On the other hand, the length of thepredetermined time is reduced if the monitor device 8 determines thatthe driver has no intention to perform the manual driving, for example.

Thus, compared with the case where the length of the predetermined timeis fixed, the autonomous driving control device according to the firstembodiment can reduce the possibility that switching from the autonomousdriving control to the manual driving occurs despite the intention ofthe driver and the possibility that the autonomous driving control ismaintained despite the intention of the driver.

In a fourth embodiment of the present invention, the monitor device 8may be omitted, or the length of the predetermined time may be fixed.

Fifth embodiment of the present invention can include thecharacteristics of the first to fourth embodiments of the presentinvention as required.

1-8. (canceled)
 9. A method of using an electronic control unit forcontrolling an autonomous driving control and a manual driving controlof a vehicle, wherein the autonomous driving control is a driving modewhich automatically controls the vehicle to travel along a travel plangenerated by a navigation system, and wherein the manual driving controlis the driving mode in which the vehicle travels based primarily on adriving operation by the driver and secondarily on a driving operationassist control that assists the driving operation by the driver, themethod comprising: starting execution of the autonomous driving control;during execution of the autonomous driving control, detecting whether anoverride operation by the driver has occurred for switching from theautonomous driving control to the manual driving control; based upon thedetection that the override operation has occurred within apredetermined time period since the autonomous driving controlautomatically started, switching the driving mode from the autonomousdriving control to the manual driving control if the override operationis equal to or more than a first predetermined threshold; and based upona detection that the override operation has occurred after thepredetermined time period since the autonomous driving controlautomatically started, switching the driving mode from the autonomousdriving control to the manual driving control if the override operationis equal to or more than a second predetermined threshold, wherein thesecond predetermined threshold is greater than the first predeterminedthreshold.
 10. The method of the using the electronic control unitaccording to claim 9, further comprising notifying the driver of thestart of the autonomous driving control.
 11. The method of using theelectronic control unit according to claim 9, further comprising using amonitoring device to monitor a state of the driver, and changing aduration of the predetermined time period based on the state of thedriver monitored by the monitor device.
 12. The method of using theelectronic control unit according to claim 9, further comprisingnotifying the driver that the first threshold is being used before thepredetermined time period elapses and that the second threshold is beingused after the predetermined time period elapses.
 13. A vehicle controldevice for controlling an autonomous driving control and a manualdriving control, wherein the autonomous driving control is a drivingmode which automatically controls the vehicle to travel along a travelplan generated by a navigation system, and wherein the manual drivingcontrol is the driving mode in which the vehicle travels based primarilyon a driving operation by the driver and secondarily on a drivingoperation assist control that assists the driving operation by thedriver, the vehicle control device comprising: an electronic controlunit programmed to: start execution of the autonomous driving control;during execution of the autonomous driving control, detect whether anoverride operation by the driver has occurred for switching from theautonomous driving control to the manual driving control; based upon adetection that the override operation has occurred within apredetermined time period since the autonomous driving controlautomatically started, switch the driving mode from the autonomousdriving control to the manual driving control if the override operationis equal to or more than a first predetermined threshold; and based uponthe detection that the override operation has occurred after thepredetermined time period since the autonomous driving controlautomatically started, switch the driving mode from the autonomousdriving control to the manual driving control if the override operationis equal to or more than a second predetermined threshold, wherein thesecond predetermined threshold is greater than the first predeterminedthreshold.
 14. The vehicle control device according to claim 13, furthercomprising a notification device that notifies the driver of the startof the autonomous driving control.
 15. The vehicle control deviceaccording to claim 13, further comprising a monitoring device to monitora state of the driver, and wherein the electronic control unit isfurther programmed to change a duration of the predetermined time periodbased on the state of the driver monitored by the monitor device. 16.The vehicle control device according to claim 13, further comprising anotification device that notifies the driver that the first threshold isbeing used before the predetermined time period elapses and that thesecond threshold is being used after the predetermined time periodelapses.
 17. A non-transitory storage medium storing instructions thatare executable by one or more processors of an electronic control unit(ECU) mounted in a vehicle and cause the one or more processors toperform functions including an autonomous driving control and a manualdriving control of a vehicle, wherein the autonomous driving control isa driving mode which automatically controls the vehicle to travel alonga travel plan generated by a navigation system, and wherein the manualdriving control is the driving mode in which the vehicle travels basedprimarily on a driving operation by the driver and secondarily on adriving operation assist control that assists the driving operation bythe driver, comprising: starting execution of the autonomous drivingcontrol; during execution of the autonomous driving control, detectingwhether an override operation by the driver has occurred for switchingfrom the autonomous driving control to the manual driving control; basedupon the detection that the override operation has occurred within apredetermined time period since the autonomous driving controlautomatically started, switching the driving mode from the autonomousdriving control to the manual driving control if the override operationis equal to or more than a first predetermined threshold; and based upona detection that the override operation has occurred after thepredetermined time period since the autonomous driving controlautomatically started, switching the driving mode from the autonomousdriving control to the manual driving control if the override operationis equal to or more than a second predetermined threshold, wherein thesecond predetermined threshold is greater than the first predeterminedthreshold.
 18. The non-transitory storage medium according to claim 17,the functions further comprising notifying the driver of the start ofthe autonomous driving control.
 19. The non-transitory storage mediumaccording to claim 17, the functions further comprising monitoring astate of the driver, and changing a duration of the predetermined timeperiod based on the state of the driver monitored by the monitor device.20. The non-transitory storage medium according to claim 17, furthercomprising notifying the driver that the first threshold is being usedbefore the predetermined time period elapses and that the secondthreshold is being used after the predetermined time period elapses.